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location  Stockholm, Sweden  
age  29  
visits  member for  4 years, 11 months 
seen  4 hours ago  
stats  profile views  8,096 
I am interested in the moduli space of curves and also other things. I am currently on parental leave.
19h

asked  Doing some homological algebra in triangulated categories 
Oct 21 
revised 
Mixed Hodge structure on configuration spaces
added 130 characters in body 
Oct 21 
comment 
Mixed Hodge structure on configuration spaces
I know this paper of Getzler; unfortunately it doesn't answer my question. He only looks at the "Euler characteristic" $\sum_k (1)^k [H^k_c(F(X,n))]$ in the Grothendieck group of mixed Hodge structures. In particular he never considers questions regarding whether extensions are nontrivial. 
Oct 21 
asked  Mixed Hodge structure on configuration spaces 
Oct 21 
answered  On the Saito Kurokawa representation 
Oct 20 
comment 
Map between stacks and automorphism groups
Your question has already been answer but let me give a really lowbrow comment. It's sometimes useful to think of a point with isotropy group of order $\vert G \vert$ as "$1/\vert G \vert$th of a point". So for instance if you have point of $M_g$ corresponding to a curve with no automorphisms, and it maps to its jacobian in $A_g$ which has the inversion automorphism, then this corresponds to "a whole point" mapping to "half of a point". This makes the map 2to1 in the sense of stacks. 
Oct 19 
comment 
A functorial isomorphism in derived category
I don't think $j$ necessary takes values in $K^+(\mathcal B)$. Look at stacks.math.columbia.edu/tag/0140 
Oct 18 
comment 
A functorial isomorphism in derived category
Why do you think my answer (to the other question) is not functorial? The truncations $\tau_{\geq n}$ are certainly functorial, and a zigzag of quasiisomorphisms in $\mathrm{Ch}(\mathcal A)$ defines functorially a morphism in $D(\mathcal A)$. And as Mariano remarks, injective resolutions can be made functorial under mild hypotheses on $\mathcal A$ (certainly satisfied for sheaves on spaces). 
Oct 16 
awarded  Nice Answer 
Oct 14 
comment 
Two basic questions on derived categories
I agree that both constructions should be functorial. 
Oct 13 
comment 
Name for series $\sum f_n x^n / (n! (n+k)!)$
I guess the case $k>0$ arises naturally as the $k$th derivative of a doubly exponential generating function. This would seem to reduce the study of "Bessel" generating series to that of doubly exponential ones. 
Oct 13 
revised 
Two basic questions on derived categories
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Oct 13 
answered  Two basic questions on derived categories 
Oct 10 
comment 
When is the Hodge diamond concentrated in $H^{n,n}$'s?
One example where the even cohomology is spanned by algebraic cycles and the odd cohomology is nonzero is the moduli space $\overline M_{1,n}$ of $n$pointed stable curves of genus one, which has odd cohomology for $n\geq 11$. 
Oct 9 
comment 
When is the Hodge diamond concentrated in $H^{n,n}$'s?
See the question mathoverflow.net/questions/151341 
Oct 8 
revised 
Why Weil group and not Absolute Galois group?
deleted 5 characters in body 
Oct 1 
comment 
$H^4(BG,\mathbb Z)$ torsion free for $G$ a connected Lie group
Don't you need $G$ to be simply connected to apply the Hurewicz theorem? 
Oct 1 
answered  Standard homology result on double complexes 
Oct 1 
comment 
(Very) High dimensional manifolds
Actually it seems the authors only prove that their example has minimal rank, not minimal dimension. Still a very nice answer. 
Sep 30 
awarded  Explainer 